A domesticated lizard has to adapt to life in the (modern) Old West in Rango, a strange and messy alleged-kids’ cartoon featuring the voice of Johnny Depp.

Rango (Depp) is a chameleon whose ability to adapt to circumstance is visible not just on his skin but also in the theatrical productions he puts on with the plastic fish, the dead bug and the half-a-Barbie who share his terrarium. But all of this changing has left him with an existential crisis about who he really is (even the name “Rango” comes from an invention later in the movie). It is at the precise moment when he is ruminating on who he is that his terrarium is bounced out of the trunk of his owner’s car onto the highway, where he scrambles to get to the white line before being squished by cars, trucks and one red convertible driven by someone bearing a strong resemblance to Hunter S. Thompson (is there an I Can Read version of Fear and Loathing in Las Vegas now?).

On the advice of a sage-sounding armadillo (Alfred Molina), Rango heads into the desert in search of water. Eventually, he runs into Miss Beans (Ilsa Fisher) a desert-dwelling lizard dressed like a Little House on the Prairie extra who is herself trying to find out where the water supply is for Dirt, her home town. She gives Rango a ride into town, a dusty place filled with lizards, frogs and assorted small burrowing mammals that make up the desert’s main wildlife. The town is hurting for water; even the weekly deluge has stopped and the Mayor (Ned Beatty) of Dirt has no solutions — though he will helpfully (or suspiciously) buy the land of anybody who wants to sell out. Rango responds to all of this by deciding to play a role, the role of gunslingin’ killed-seven-outlaws-with-one-bullet white hat. The Mayor decides to make him sheriff, which means its Rango’s job to protect the last bit of water that serves as currency at the town bank and to protect the townsfolk from the hawk that menaces them from time to time. Rango does defeat the hawk — but without a hawk to fear, Jake (Bill Nighy), the local black hat rattlesnake, may now be coming to town.

What seven-year-old hasn’t been asking for a movie about water rights in the West and featuring as villains a real estate developer and a giant rattlesnake? (A rattlesnake who is not only larger than the other animals and possessed of venom-injecting fangs but whose rattle is also the barrel of a gun — good luck getting the kids to sleep after this.)

Rango is a spur-wearing, yee-haw-ing mess. It winds up a crazy carousel of animal wackery and jittery Deppness and then screeches the action to a halt so Rango can consider his identity. It spends a lot of time on the rather dry subject of water and then throws in a lot of rather frightful-looking animals to serve as villains or at least villainy-inclined. With its spaghetti western references and its scattered approach to the story, the movie seems like it would appeal to neither kid nor adult — both over kids’ heads and not fun enough for grown-ups. There seemed like a good amount of kid-fidgeting in the theater where I saw this movie — I heard a lot of moving around in seats, a lot of discussion with parents and not a whole lot of laughing. There are kids’ movies where I personally get so wrapped up in the story (Toy Story 3) that I don’t even notice the audience response and there are movies that are big boisterous fun for everybody in the audience (Despicable Me). Rango was neither. It felt oddly paced and shakily constructed from the beginning — too much inner life of a lizard before we establish why we should care about any facet of his personality.

Rango looked good — I liked the way the movie draws its dusty little town and its strange inhabitants — but it isn’t a pretty-looking movie. And plenty of characters and even landscape features seem like they could be downright terrifying to little kids. I must say I was delighted that the movie isn’t in 3-D. I give the movie credit for not adding that extra layer of lunacy to its disjointed and strangely paced makeup.

C

Rated PG for rude humor, language, action and smoking. Directed by Gore Verbinski and written by John Logan, Gore Verbinsk and. James Ward Byrkit, Rango is an hour and 47 minutes long and is distributed by Paramount Pictures. It opens in wide release on Friday, March 4.